Thin insulators, no recessing of window & door frames?

joel_bcMay 11, 2008

Hi. I live in a 2x4 frame house with fiberglass-bat insulation (built 1978). We're in plant-zone 6 and get a coldish winter, hot mid-summer (but not as cold a winter as much of the rest of Canada). About a year ago, I read about a highly reflective paint layer that has been developed - remove your exterior siding, paint it on the inside of the siding, replace, and you supposedly have a significantly improved R value, due to reflected heat.

I don't know how true this is, about this sort of product. But it's made me wonder if there IS some thin (possibly quarter-inch) material that can be installed under siding that can significantly increase R value, without resulting in recessed window and door frames. By the way my house was originally built with black-building paper over plywood sheathing behind the siding, and with a plastic-sheet vapor barrier on the interior behind the drywall or wood panelling.

What do you know of about thin insulating products? And, if such products exist, are there down sides to using them in a house like mine? And how costly are these materials? Thanks.

I would do some Googling to research it more carefully, get some actual figures on pre- and post-painting results and where those houses are located weather-wise. It also sounds like it wouldn't be an inexpensive job, and probably quite tiring to live through. If your regular insulation is not doing the job, and you've been assessed by the gov't re heat loss from other sources, then I'd be more likely to look to some of those before going the paint route.

A few bits of clarification. For one, I'm in rural western Canada and the government isn't coming down on me... I just would like to burn a little less than four cords of wood in the cold season (even though people tell me that for a two-storey, 2650 sq ft home, four cords is not bad).

Second, I'm a do-it-yourselfer and would do my own work, removing siding and adding a coating or applying thin insulation sheeting - though perhaps I'd hire a helper for two or three days.

To add to these basics, I'll just say that I've got double-pane windows but plan to add night-time heat-retaining shutters to those windows and glass doors that at present don't have heavy curtains to be closed over them at night.

I've posted here to get an informal 'consumer's report' on varied possible products/materials from other people who may have done a home upgrade (heat retention-wise) similar to what I'm contemplating.

No no - I didn't mean the gov't was coming down on you, but (being a Canuck myself) the gov't will come in (for a small fee) and do a complete once over of your home and find any small or large leaks, and assess your current insulation and recommend fixes. Without that, with the possibility of air going straight out the top of the house or windows, or elec. outlets, etc., in various ways you can end up pouring lots of money into insulation, but it won't help as much as some sealing up of existing leaks.

You already have good materials - the black building paper, the insulation and vapor barrier. The paint is about as good as painting the space behind radiators silver - better than painting it black, but not terribly effective.
First, I would try tightening up - as Lucy suggests. Go around the house with a candle and watch where the flame goes sideways to see where you have air infiltration. Then caulk and repair.

Storm windows, heavy winter drapes that you use, shutters, storm doors, closing up a exterior door in winter, heating less space by living in less, bookcases or tapestries on exterior walls! Try those before you take off siding for a layer of paint!
The Old House Journal forum had questions about a similar paint earlier this year - see if you can find the thread.

Joel-
Unfortunately, there's no wonder material that's only 1/4" thick that will greatly increase R-value. If it existed, it would be used instead of all those 6", 8", and 10" batts of insulation. I've also heard about the paint, and I don't think it would change your energy consumption noticeably, and it certainly wouldn't be worth the trouble of removing the siding. If it worked, you could get the same effect without taking off the siding by painting it on the outside of the siding and then covering that coat with another coat of paint.

kudzu9 wrote: "I've also heard about the paint, and I don't think it would change your energy consumption noticeably, and it certainly wouldn't be worth the trouble of removing the siding. If it worked, you could get the same effect without taking off the siding by painting it on the outside of the siding and then covering that coat with another coat of paint."

Well, even if the paint DID work, I'd paint it on the underside of the siding boards, because my boards are natural-wood-finish (bandsawed texture & coating of preservative), and I would want to keep that.

And kudzu9 wrote "Unfortunately, there's no wonder material that's only 1/4" thick that will greatly increase R-value. If it existed, it would be used instead of all those 6", 8", and 10" batts of insulation."

Hmmm... maybe there is no thin insulating board.

On the other hand, 2-inch-thick ISO board has an R value of 14, which is like that of 4 inches of fiberglass batt. So here's an example of a thinner material that is known and used (but for one thing, ISO board is expensive so it is true that it's not used as much for wall insulation as the batts).

If thinner insulation materials of high R value exist and are on the market, it could be they are not in as common usage due to the cost factor. Still, those of us ready to spend the cost of increasing our home walls' insulation - especially when we're DIY people who save on the labor costs - might sometimes be interested in a somewhat expensive product. If such exists...

At the moment foam insulation has the highest R-value and possibly could be installed in a very thin layer. I am trying to imagine how.
One big factor in R value is air infiltration from cracks. The foam eliminates those - any sheet insulation automatically includes air spaces.

joel-
I live in the Pacific NW and have had homes with your type of siding, so I understand that you want to keep that appearance. I assumed you had siding that had a solid finish, and repainting would not alter it. Now that I know what you have, I will re-emphasize not trying to remove it: the possibility of splits, cracking, and breaking would make for a very difficult experience...and I'm speaking as someone who is fairly handy and had to do this once on a section of my house.

I will also wanted to emphasize that I didn't say there were no thin insulating materials, just none that had much R-value. Foam re-siding board 1/4" thick has an R of 1, and that's not much change in a wall. If you already have some insulation in your walls, increasing by R-1 will make only a small change in energy consumption. If your walls have no insulation, then I suggest you have insulation blown in which will give you a significant change in R value, and will not involve all the nasty work of siding removal.

I'm not against increasing insulation...I spent part of my career doing energy conservation work. I'm just not in favor of someone doing a lot of work and getting little or nothing back on their investment. Good luck.

jegr wrote: "One big factor in R value is air infiltration from cracks. The foam eliminates those - any sheet insulation automatically includes air spaces."

Yes, you and others have emphasized this. Over the last ten or twelve years, I've sought out the cracks and spaces (e.g., around doors, windows, and in-wall electrical boxes) in order to fill them and reduce or stop infiltration. Also, besides how I described the exterior-wall vapor barrier and fiberglass insulation, I've got 10" of vermiculite between the second-floor ceiling rafter (it was in place when we bought the house).

As I say, people in my valley who know houses of my own's vintage (late 1970s) say my fuel consumption is pretty low. But I've wanted to keep improving it for reasons of both a practical and a commitment nature.

Maybe at this point there is no genuine and significantly effective means of doing this, without having to replace window and door casings.

On another forum, someone mentioned that they had heard of some new (foam?) insulation that's 1/2-inch thick that is reputed to have a very high R value. When I then questioned the person who posted, for more info, I got no response.

Does anyone here know what this person may have been referring to?

New technologies & products hit the market all the time, so I want to keep up. Maybe something is becoming available that will fit the bill for me.

brickeyee, hmmm... Thanks for proffering a suggestion, but ss I mentioned a couple times, the house has 2x4 framing, with 3.5" of fiberglass insulation in the exterior walls. No room for blown-in cellulose.

Just wondering if anything new in the way of a thin (say, 1/4 - 1/2") wonder product has hit the market in the last months. On another forum on which I pitched the same question, someone mentioned they thought there was a highly heat-reflective or insulative half-inch board that had become available, but when I inquired the info poster did not respond. Leaving me in the dark as to whether some valid product has or has not come on market.

Sorry Joel - the laws of thermodynamics still apply to your home. I assume the other poster was talking about something like a foil coated Polyurethane rigid panel. Straight from the factory, you could get an R9 per inch out of the high end stuff but it degrades over a couple of years to R7 or so. Still, at 1/2 that would get you an additional 3.5. It probably isn't going to be cost effective for you, but if you only have R11 in the walls, it might make the house more comfortable. It sounds like an awful lot of work for minimal benefit though.

Did you get the shutters or curtains up yet? That would be a much cheaper and cost effective way to keep the heat in. I assume your double pane windows are still only in the R3 range. That means you are losing 3-4 times more energy though each square foot of window than you are through the walls. Depending on the size of your windows, a good set of curtains might save more energy than marginally increasing the R value of the walls.

The previous posters have mentioned a number of cost-effective methods of reducing heat loss. Another often overlooked source of heat loss is the first few feet of the basement, assuming you have one. Professionally foaming the rim joist area, or tightly sealing it with xps foam board will make a large improvement.

BTW, don't wander around in that 10" of very likely asbestos-laden vermiculite in your attic.

Worthy, this is an interesting suggestion. It's true: I do have a basement and I've never done any sealing around the rim joist area.

I'm curious about why you say have it professionally sealed. Is there no DIY method that I could utilize myself? (I'm a pretty handy guy, and used to work sometimes as an assistant to pro masons and carpenters, and as part of a concrete-form team. Plus I have experience with the sort of insulating foam that comes in a can at the building-supply store.)

As a builder, I find it more economical to use cc foam professionally sprayed rather than try and find anyone to do this by hand. The spray is fast, seals all irregularities and is not messy. Unlike the picture below, clear access to the rim--especially in an already completed home--is often difficult. And, in contrast to the pic below, many hand foams can only be use when the can is upside down. Even with flexible applicators, you can end up with more foam on the floor than in the cracks. But if you have the time and patience, it can be done. Note: don't use fg anywhere in the rim or the blocks.